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Abstract:

A stereoscopic display device includes a display panel for displaying an
image, a parallax barrier having a first barrier region to an Nth barrier
region and a first distance between the parallax barrier and the display
panel, the first barrier region to the Nth barrier region respectively
having a first barrier pitch to a Nth barrier pitch, a
detection-and-calculation device for detecting a second distance between
the display panel and an observer, and a parallax barrier adjustment
device for selecting one barrier region from the first barrier region to
Nth barrier region.

Claims:

1. A stereoscopic display device comprising: a display panel for
displaying an image; a parallax barrier having a first barrier region to
an Nth barrier region and a first distance between the parallax barrier
and the display panel, the first barrier region to the Nth barrier region
respectively having a first barrier pitch to a Nth barrier pitch; a
detection-and-calculation device for detecting a second distance between
the display panel and an observer; and a parallax barrier adjustment
device for selecting one barrier region from the first barrier region to
Nth barrier region.

4. The stereoscopic display device of claim 1, wherein the parallax
barrier adjustment device comprises a stepping motor and a roll, and the
parallax barrier adjustment device selects one barrier region from the
first barrier region to the Nth barrier region of the parallax barrier by
rotating the roll.

5. A stereoscopic display device comprising: a display panel for
displaying an image; a parallax barrier and an adjustable first distance
between the parallax barrier and the display panel; a
detection-and-calculation device for detecting a second distance between
the display panel and an observer and a third distance between two eyes
and a center of the two eyes of the observer; and a parallax barrier
distance adjustment device for adjusting the adjustable first distance.

6. The stereoscopic display device of claim 5, wherein the
detection-and-calculation device comprises at least an image device and a
distance meter.

Description:

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention is related to a stereoscopic image displaying
method and a stereoscopic display device, and more particularly, to a
stereoscopic image displaying method providing different viewing
distances and a stereoscopic display device for different viewing
distances.

[0003] 2. Description of the Prior Art

[0004] Stereoscopic display technique is developed to provide two separate
images individually to the left and right eyes of an observer, and thus
the observer obtains a stereoscopic vision.

[0005] The conventional stereoscopic display devices can be classified
into passive approach and active approach: The passive approach involves
using of eyewear such as polarized glasses or shutter glasses while the
active approach provides 3D images without assistance as mentioned above.
Conventionally, the active approach involves techniques such as the
parallax barrier.

[0006] Please refer to FIG. 1, which is a schematic drawing illustrating
optical paths of a conventional stereoscopic display device employing a
parallax barrier. As shown in FIG. 1, the conventional stereoscopic
display device 100 includes a liquid crystal display (LCD) panel 110 and
a parallax barrier 120. The LCD panel 110 provides a left eye image L and
a right eye image R, and the parallax barrier 120, such as an optical
grating, includes a plurality of shading regions 122 and transparent
regions 124 alternately and repetitively arranged for separating the left
eye image L and the right eye image R. Such that the observer can
perceive the left eye image L and the right eye image R individually and
obtain the 3D stereoscopic images.

[0007] It is noteworthy that the left eye image L and the right eye image
R provided by the LCD panel 110 have a same pixel pitch 130, which is
predetermined and fixed. Furthermore, the shading regions 122 and the
transparent regions 124 of the parallax barrier 120 have the same barrier
pitches 132, which are determined according to a distance 134 between the
parallax barrier 120 and the LCD panel 110, an ideal viewing distance 136
between the observer and the LCD panel 110, and a distance 138 between
two eyes and a center of two eyes of the observer. As shown in FIG. 1,
the observer perceives the desired 3D stereoscopic images at a spot
satisfied the viewing distance 136. But when the observer leaves the
spot, no stereoscopic images are observed.

[0008] In other words, the conventional stereoscopic display device
employing the parallax barrier provides an unchangeably fixed ideal
viewing distance. When the observer has to change the real viewing
distance, the real viewing distance not matching the fixed ideal viewing
distance makes the observer cannot obtain the stereoscopic images.
Consequently, the stereoscopic display device having the parallax barrier
provides stereoscopic images in a limited space.

SUMMARY OF THE INVENTION

[0009] Therefore the present invention provides a stereoscopic image
displaying method able to provide different viewing distances and a
stereoscopic display device for different viewing distances.

[0010] According to a first aspect of the present invention, a
stereoscopic display device is provided. The stereoscopic display device
includes a display panel for displaying an image, a parallax barrier
having a first barrier region to an Nth barrier region and a first
distance between the parallax barrier and the display panel, the first
barrier region to the Nth barrier region respectively having a first
barrier pitch to a Nth barrier pitch, a detection-and-calculation device
for detecting a second distance between the display panel and an
observer, and a parallax barrier adjustment device for selecting one
barrier region from the first barrier region to Nth barrier region.

[0011] According to a second aspect of the present invention, another
stereoscopic display device is provided. The stereoscopic display device
includes a display panel for displaying an image, a parallax barrier and
an adjustable first distance between the parallax barrier and the display
panel, a detection-and-calculation device for detecting a second distance
between the display panel and an observer and a third distance between
two eyes and a center of the two eyes of the observer, and a parallax
barrier distance adjustment device for adjusting the adjustable first
distance.

[0012] According to the stereoscopic display devices provided by the
present invention, different viewing distances are obtained by providing
barrier regions having different barrier pitches or by providing
different distances between the parallax barrier and the display panel.
Therefore, when the observer increases or reduces the real viewing
distance, the stereoscopic image displaying method and the stereoscopic
display device provided by the present invention always provide 3D
stereoscopic images of high quality.

[0013] These and other objectives of the present invention will no doubt
become obvious to those of ordinary skill in the art after reading the
following detailed description of the preferred embodiment that is
illustrated in the various figures and drawings.

[0021] Certain terms are used throughout the description and following
claims to refer to particular components. As one skilled in the art will
appreciate, electronic equipment manufacturers may refer to a component
by different names. This document does not intend to distinguish between
components that differ in name but not function. In the following
description and in the claims, the terms "include" and "comprise" are
used in an open-ended fashion, and thus should be interpreted to mean
"include, but not limited to . . . ".

[0022] Please refer to FIGS. 2-5, wherein FIG. 2 is a schematic drawing
illustrating a stereoscopic image displaying method and a stereoscopic
display device provided by a first preferred embodiment of the present
invention, FIGS. 3-4 are schematic drawings illustrating different
optical paths of the preferred embodiment in different operations, and
FIG. 5 is a schematic drawing illustrating a modification to the
preferred embodiment. Please refer to FIGS. 2-4. A stereoscopic display
device 200 provided by the preferred embodiment includes a display panel
210 for displaying an image. The display panel 210 can be a liquid
crystal display (LCD) panel accompanied with a backlight module (not
shown), but not limited to this. The image provided by the display panel
210 is divided into a left eye image L and a right eye image R (shown in
FIG. 3 and FIG. 4) according to the preferred embodiment. The adjacent
left eye image L and right eye image R respectively has a pixel pitch "i"
formed therebetween. The stereoscopic display device 200 further includes
a parallax barrier 220 and a first distance "g" between the parallax
barrier 220 and the display panel 210. The parallax barrier 220 includes
a first barrier region 2201 to an Nth barrier region 220N. The first
barrier region 2201 has a plurality of shading regions 2221 and a
plurality of transparent regions 2241. In the same concept the Nth
barrier region 220N also has a plurality of shading regions 222N and a
plurality of transparent regions 224N. The shading region 2221 and the
transparent region 2241 of the first barrier region 2201 include a first
barrier pitch b1. In the same concept, the shading region 222N and
the transparent region 224N of the Nth barrier region 220N also include a
Nth barrier pitch bn. In other words, the shading regions 2221 and
transparent regions 2241 that have strip patterns construct the first
barrier region 2201 and each strip pattern has the same width, which is
the first barrier pitch b1. In the same concept, the shading regions
222N and the transparent regions 224N that have strip patterns construct
the Nth barrier region 220N, and each strip pattern has the same width,
that is the Nth barrier pitch bn. More important, the first barrier
pitch b1 to the Nth barrier pitch bn are different from each
other. It is noteworthy that in the preferred embodiment, the parallax
barrier 220 is positioned in front of the display panel 210, but it is
not limited to position the parallax barrier 220 behind the display panel
210, in particularly, to position the parallax barrier 220 between the
display panel 210 and the backlight module in the present invention.

[0023] Please refer to FIGS. 2-4. The stereoscopic display device 200
provided by the preferred embodiment further includes a
detection-and-calculation device 230 for detecting a second distance "z",
namely the viewing distance, between the display panel 210 and an
observer. The detection-and-calculation device 230 includes at least a
computing circuit (not shown) and a distance meter 232. The
detection-and-calculation device 230 further selectively includes an
image device 234. The distance meter 232 can include an infrared distance
meter or a Laser distance meter, but not limited to this. Those skilled
in the art would realize that any equipment that is used to detect second
distance "z" between the observer and the display panel 210 can be used.
Furthermore, the stereoscopic display device 200 includes a parallax
barrier adjustment device 240. The parallax barrier adjustment device 240
can include a roller 242 and a rotary stepping motor 244. The parallax
barrier adjustment device 240 can be positioned on the top/bottom sides
of the stereoscopic display device 200 as shown in FIG. 2; it also can be
positioned on the left/right sides of the stereoscopic display device 200
as shown in FIG. 5.

[0024] According to the stereoscopic image displaying method provided by
the preferred embodiment, it first provides the display panel 210 and the
parallax barrier 220 as mentioned above. Then, the second distance "z"
between the display panel 210 and the observer is detected by the
distance meter 232 of the detection-and-calculation device 230. After
obtaining the second distance "z" from the distance meter 232, the
computing circuit is operated to obtain an ideal barrier pitch "13,"
according to a formula (1):

b = 2 i ( z - g z ) ( 1 ) ##EQU00001##

[0025] According to the formula (1), it is found the barrier pitch "b" is
always corresponding to the second distance "z" because the pixel pitch
"i" and the first distance "g" are predetermined and fixed. In other
words, ideal barrier pitches bi suited for different viewing
distances are obtained by the detection-and-calculation device 230
according to the preferred embodiment.

[0026] Please refer to the following exemplars: As shown in FIG. 3 and
FIG. 4, the pixel pitch "i" of the display panel 210 is 0.1 millimeter
(mm) in and the first distance "g" between the display panel 210 and the
parallax barrier 220 is 1.15 mm in the preferred embodiment, which are
all predetermined and fixed. When different second distances "z" between
the observer and the display panel 210 are detected by the
detection-and-calculation device 230, different ideal barrier pitches
"bi" are obtained according to formula (1), as shown in Table 1:

[0027] According to the different ideal barrier pitches "bi" that are
suited for different second distances "z", the rotary stepping motor 244
of the parallax barrier adjustment device 240 is used to select a barrier
region that has the barrier pitch "b" equal to the ideal barrier pitch
"bi" from the parallax barrier 220 by rotating the roll 242. As
shown in FIG. 3, when the second distance "z" is exemplarily 750 mm, the
rotary stepping motor 244 and the roller 242 select a proper barrier
region such as the first barrier region 2201 having the barrier pitch
"b1" of 0.1996933 mm, that is equal to the ideal barrier pitch
"bi", from the first barrier region 2201 to the Nth barrier region
220N of the parallax barrier 220. Therefore, the observer obtains the
stereoscopic images at said viewing distance. In another exemplar as
shown in FIG. 4, when the second distance "z" is exemplarily 400 mm, the
rotary stepping motor 244 and the roller 242 selects another proper
barrier region such as the barrier region 2203 having the barrier pitch
b3 of 0.199425 mm that is equal to the ideal barrier pitch "bi"
from the first barrier region 2201 to the Nth barrier region 220N of the
parallax barrier 220. Therefore, the observer still obtains the
stereoscopic images at said viewing distance.

[0028] According to the stereoscopic image displaying method and the
stereoscopic display device of the first preferred embodiment, different
viewing distances are obtained by providing different barrier regions
having different barrier pitches. When the observer increases or reduces
the viewing distance, the detection-and-calculation device of the
stereoscopic display device of the present invention is utilized to
detect the second distance "z" (the real viewing distance) between the
observer and the display panel 210, and thus an ideal barrier pitch
"bi" is obtained. Accordingly, a proper barrier region is selected
from the first barrier region 2201 to the Nth barrier region 220N of the
parallax barrier 220 by the parallax barrier adjustment device 240. In
other words, the parallax barrier adjustment device 240 is used to select
a proper barrier pitch that is equal to the ideal barrier pitch
"bi", from the first barrier pitch "b1" to the Nth barrier
pitch "bn". Briefly speaking, when the observer increases or reduces
the real viewing distance, the stereoscopic image displaying method and
the stereoscopic display device of the first preferred embodiment always
provides 3D stereoscopic images of high quality by providing a proper
barrier region suited for the real viewing distance.

[0029] Please refer to FIGS. 6-10, wherein FIG. 6 is a schematic drawing
illustrating a stereoscopic image displaying method and a stereoscopic
display device provided by a second preferred embodiment of the present
invention, FIGS. 7-8 are schematic drawings illustrating different
optical paths of the preferred embodiment in different operations, and
FIGS. 9-10 are schematic drawings illustrating modifications to the
preferred embodiment. As shown in FIG. 6, a stereoscopic display device
300 having a display panel 310 and a backlight module (not shown) is
provided by the preferred embodiment. The display panel 310 provides an
image, and the image is divided into a left eye image L and a right eye
image R (shown in FIG. 7 and FIG. 8) according to the preferred
embodiment. The left eye image L and the right eye image R respectively
have a pixel pitch "i" formed therebetween. The stereoscopic display
device 300 further includes a parallax barrier 320 constructed by a
plurality of shading regions 322 and a plurality of transparent regions
324 in stripe patterns (shown in FIG. 7 and FIG. 8). More important, the
stereoscopic display device 300 includes an adjustable first distance
"ga" between the parallax barrier 320 and the display panel 310. The
parallax barrier 320 is positioned in front of the display panel 310.
However, it is not limited to position the parallax barrier 320 between
the display panel 310 and the backlight module in the present invention.

[0030] Please still refer to FIG. 6. The stereoscopic display device 300
of the preferred embodiment also includes a detection-and-calculation
device 330. The detection-and-calculation device 330 is used to detect a
second distance "z", that is the viewing distance, between the display
panel 310 and an observer. The detection-and-calculation device 330
includes at least a computing circuit (not shown), a distance meter 332,
and an image device 334. The distance meter 332 can be an infrared
distance meter or a Laser distance meter, but not limited to this. The
image device 334 can be a charge coupled device but not limited to this.
The distance meter 332 is used to detect the second distance "z" between
the observer and the display panel 310 and the image device 334 is used
to detect a third distance "e" between two eyes and a center of the two
eyes of the observer. Additionally, the third distance "e" is a detected
value in the preferred embodiment, but it also can be a predetermined
value.

[0031] According to the stereoscopic image displaying method of the
preferred embodiment, the display panel 310 and the parallax barrier 320
is provided. Then, the distance meter 332 and the image device 334 of the
detection-and-calculation device 330 are used to detect the second
distance "z" between the display panel 310 and the observer and the third
distance "e" between the two eyes and the center of the two eyes of the
observer. After obtaining the second distance "z" and the third distance
"e" from the distance meter 332 and the image device 334, the computing
circuit is operated to obtain an ideal first distance "gi" according
to a formula (2):

z = g ( e + i i ) ( 2 ) ##EQU00002##

[0032] According to the formula (2), it is found the first distance "g" is
always corresponding to the second distance "z" and the third distance
"e" because the pixel pitch "i" is predetermined and fixed. In other
words, ideal first distances "gi" suited for different second
differences "z" and different third distances "e" are obtained by the
detection-and-calculation device 330 according to the preferred
embodiment.

[0033] As shown in FIG. 7 and FIG. 8, the pixel pitch "i" of the display
panel 310 is 0.1 mm in the preferred embodiment. In an exemplar, the
third distance "e" between the two eyes and the center of the two eyes of
the observer can be 75 mm or 50 mm in the preferred embodiment. When
different second distances "z" are detected by the
detection-and-calculation device 330, different ideal first distance
"gi" are obtained according the abovementioned formula (2), as shown
in Table 2:

[0034] The stereoscopic display device 300 of the present invention
further includes a parallax barrier distance adjustment device 340.
(shown in FIG. 9 and FIG. 10) According to different second distances "z"
and different third distances "e" detected by the
detection-and-calculation device 330, different ideal first distance
"gi" are obtained. Consequently, the adjustable first distance
"ga" between the parallax barrier 320 and the display panel 310 is
adjusted to be equal to the ideal first distance "gi" by the
parallax barrier distance adjustment device 340. Therefore the observer
positioned at different second distances "z" still obtains 3D
stereoscopic images. As shown in FIG. 7, when the detected second
distance "z" is exemplarily 750 mm and the detected third distance "e" is
exemplarily 75 mm, the parallax barrier distance adjustment device 340 as
shown in FIG. 9 and FIG. 10 is utilized to adjust the adjustable first
distance "ga" to 0.998668 mm, that is equal to the ideal first
distance "gi". Therefore the observer obtains the stereoscopic
images at said viewing distance. In another exemplar as shown in FIG. 8,
when the detected second distance "z" is exemplarily 400 mm and the
detected third distance "e" is exemplarily 50 mm, the parallax barrier
distance adjustment device 340 is utilized to adjust the adjustable first
distance "ga" to 0.798403 mm, that is equal to the ideal first
distance "gi". Therefore the observer still obtains stereoscopic
images at said viewing distance.

[0035] Please refer to FIG. 9 and FIG. 10, the parallax barrier distance
adjustment device 340 of the stereoscopic display device 300 can be a
telescoping tube 342 as shown in FIG. 9. When setting up the stereoscopic
display device 300, the working staff adjusts the telescoping tube 342 to
make the adjustable first distance "ga" equal to the ideal first
distance "gi" that is obtained by the detection-and-calculation
device 330. Furthermore, the barrier distance adjustment device 340 can
include a stepping motor 344 and a track 346 with the parallax barrier
320 connected to the stepping motor 344 and positioned on the track 346
as shown in FIG. 10. Every time when the stereoscopic display device 300
is turned on, the second distance "z" and the third distance "e" are
detected by the detection-and-calculation device 330 and thus the ideal
first distance "gi" is obtained. Consequently, the stepping motor
344 is used to adjust the parallax barrier 320 positioned on the track
346 to make the adjustable first distance "ga" between the parallax
barrier 320 and the display panel 310 equal to the ideal first distance
"gi". Accordingly, the observer always obtains stereoscopic images
in different second distances "z".

[0036] According to the stereoscopic image displaying method and the
stereoscopic display device of the second preferred embodiment, different
viewing distances are obtained by adjusting the adjustable first distance
"ga": when the observer increases or reduces the real viewing
distance, the detection-and-calculation device 330 of the stereoscopic
display device of the present invention is utilized to detect the second
distance "z" (the real viewing distance) between the observer and the
display panel 310, and thus an ideal first distance "gi" is
obtained. Subsequently, the parallax barrier adjustment device 340 is
used to adjust the adjustable first distance "ga" to be equal to the
ideal first distance "gi". Briefly speaking, when the observer
increases or reduces the real viewing distance, the stereoscopic image
displaying method and the stereoscopic display device of the first
preferred embodiment still provides 3D stereoscopic images of high
quality. Briefly speaking, when the observer increases or reduces the
real viewing distance, the stereoscopic image displaying method and the
stereoscopic display device of the second preferred embodiment always
provides 3D stereoscopic images of high quality by providing a proper
adjustable first distance "ga" suited for the real viewing distance.

[0037] According to the stereoscopic image displaying method and the
stereoscopic display device provided by the present invention, different
viewing distances are obtained by providing barrier regions having
different barrier pitches or by providing different distances between the
parallax barrier and the display panel. Therefore, when the observer
increases or reduces the real viewing distance, the stereoscopic image
displaying method and the stereoscopic display device provided by the
present invention always provide 3D stereoscopic images of high quality.

[0038] Those skilled in the art will readily observe that numerous
modifications and alterations of the device and method may be made while
retaining the teachings of the invention.